###Live Caption:Roger Doughty, executive director of the Horizons Foundation, thanks Joseph Rosenthal for transferring his estate holdings to Horizons in San Francisco, Calif., on Thursday, March 6, 2008. Many philanthropists in the gay community are bequeathing their estates to LGBT endowments.
Photo by Paul Chinn / San Francisco Chronicle###Caption History:Roger Doughty, executive director of the Horizons Foundation, thanks Joseph Rosenthal for transferring his estate holdings to Horizons in San Francisco, Calif., on Thursday, March 6, 2008. Many philanthropists in the gay community are bequeathing their estates to LGBT endowments.
Photo by Paul Chinn / San Francisco Chronicle###Notes:Roger Doughty, Joseph Rosenthal###Special Instructions:MANDATORY CREDIT FOR PHOTOGRAPHER AND S.F. CHRONICLE/NO SALES - MAGS OUT

On a recent Thursday morning, Joseph Rosenthal, 77, drove from his barn-red, four-story house on Buena Vista Terrace to a lawyer's office in the Castro, where he quietly transferred a substantial part of his estate to the endowment fund of the Horizon Foundation, a grant-giving organization for the gay, lesbian, bisexual and transgender community.

"I have almost no family living at this time," said Rosenthal, a retired librarian. "Certainly, not having children prompts one to consider other options, such as supporting charitable organizations in the area of my particular interest."

The lesbian, gay, bisexual and transgender movement has traditionally depended on smaller, grassroots donations for specific causes. But more aging philanthropists like Rosenthal, whose generation was the first to be "out," are making end-of-life gifts to help secure the future of the community.

"If I had died in 1980, I would have had no idea that the HIV epidemic was around the corner," said retired venture capitalist David Gleba, 45, who has contributed more than $250,000 to the Horizon Foundation. "After I am gone, I would like to see the part of my estate continue to work in succeeding the younger generation."

In the past three decades, gay philanthropies such as Horizon Foundation, Pride Foundation and Astraea Lesbian Foundation for Justice have helped shape today's lesbian and gay community, funneling millions of dollars into numerous HIV/AIDS treatment services, and civil rights, social advocacy and political campaigns. According to a group that advises grantmakers, New York-based Funders for Lesbian and Gay Issues, grants made to gay organizations nationwide have more than doubled from under $30 million in 2002 to $65.5 million in 2006.

"People feel more security that we are here to stay and we are fulfilling a purpose, so more are thinking of LGBT foundations as places to leave their bequests," said Katherine Acey, executive director of the Astraea Lesbian Foundation for Justice, a New York-based organization that supports groups in more than 40 countries. "I see the beginning of a trend."

A new record for bequests was set earlier this month, when former Microsoft employee Ric Weiland, who died in 2006, left $65 million to the Pride Foundation and several other organizations, said to be the largest gift ever made to the gay community in the United States.

While few would be able to match Weiland's generosity, many gay and lesbian donors, who usually don't have children, are likely to consider end-of-life gifts, philanthropy experts say.

"In the past two years, we have seen a huge upswing" in estate donations, said Zan McColloch-Lussier, spokesman for the Pride Foundation, which estimates that each year about 30 donors include the organization in their wills. "And we know that we only hear about the small percent of those who are actually planning to do it."

According to a survey of 1,300 donors conducted by the Horizon Foundation, for example, about 52 percent said they are "very likely" to make estate gifts to the gay and lesbian movement, while 87 percent think it is "important" and "very important" to them to "help future generations." The foundation estimates it will receive at least $35 million in future estate gifts to its lesbian, gay, bisexual and transgender endowment fund.

"The success of this vision does not depend on any assumption that LGBT people are richer than the non-LGBT population," said Roger Doughty, the executive director of the foundation. "All our projections are based on assumptions that we are 'average,' except that fewer of us have children and the lives of many reaching their 'planned giving years' have been deeply touched by the growth, struggles, and triumphs of the LGBT movement."

Jeff Lewis, 65, who said he is a substantial donor to the gay community, became active in political fundraising and philanthropy during the failed Briggs Initiative of 1978, which would have banned gays and lesbians from teaching in California's public schools.

Thirty years later, despite major changes in the society, Lewis said the gay movement still faces opposition from conservative groups and needs financial support to help fight for its civil rights.

"Given the political situation we have been in the last 10 years, we have more to gain through the courts than through the other outlets," said Lewis, who came out to his friends more than 40 years ago. Donating to endowments "is an important way to change the situation in the longer term."

Many gay and lesbian philanthropies nationwide are vying to tap the lucrative market of an aging gay population. Horizon Foundation, which wants to raise its endowment to $100 million over 25 years, collaborates with professional financial advisers and estate-planning attorneys, sponsoring seminars around planned giving. Astraea foundation has created the Women's Will Circle, a program that helps publicize donors who have included the foundation in their estates. The OutGiving campaign of the Gill Foundation, created by Tim Gill, the inventor of Quark software, recruits philanthropists to secure large-scale and long-term financial support for the gay, lesbian, bisexual and transgender community.

"As a society, we are more open talking about bequests than we were before," said Liz Livingston Howard, an associate director of the Center for Nonprofit Management at Northwestern University. "It speaks of the sophistication of nonprofit organizations being more focused on long-term sustainability and insuring their future."